Asymmetric synthesis of multiple quaternary stereocentre-containing cyclopentyls by oxazolidinone-promoted Nazarov cyclizations. Issue 20 (2nd May 2018)

• Record Type: Journal Article
• Authors: Volpe, Rohan; Lepage, Romain J.; White, Jonathan M.; Krenske, Elizabeth H.; Flynn, Bernard L.
• Is Part Of: Chemical science. Volume 9:Issue 20(2018)
• Page Start: 4644
• Page End: 4649
• Publication Date: 2018-05-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8sc00031j
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Ox -activated divinyl ketones undergo torquoselective Nazarov cyclization to give cyclopentanoids containing up to three new contiguous quaternary (4°) stereocentres. Abstract : Carbometalation of oxazolidinone (Ox )-substituted ynamides is used to generate highly substitutedOx -divinyl (and aryl vinyl) ketones for use in Nazarov cyclizations. TheOx -group serves as a remarkably effective chiral activating group, enabling the torquoselective Nazarov cyclization of these sterically congested substrates to be performed under mild conditions. It also serves as a charge-stabilizing group in the intermediate oxyallyl cation, suppressing undesired [1, 2]-sigmatropic shifts of neighboring substituents and facilitating the regio- and stereoselective incorporation of nucleophiles to yield cyclopentanoids containing up to three contiguous all-carbon quaternary (4°) stereocentres.